Many of the world's top food companies are not doing enough to help cut the salt, fat and sugar which are contributing to a global, diet-related health crisis, according to a report on Tuesday.

It called the response of the top 25 firms pathetic and said many only changed their ways when faced with bad publicity.

The report, by London's City University, looked at how the companies had responded to targets set in 2004 by the World Health Organisation (WHO) to tackle obesity, heart disease and diabetes.

The group studied annual reports, accounts and Web sites of the top 10 food manufacturers, top 10 food retailers and top five food service companies.

The research is the first attempt to monitor whether and how these powerful companies are reporting on their impact on diet and health, the report said.

We set out to shine a light on what these mostly publicly quoted companies are doing, or report they are doing. Our findings are worrying.

The study found that only 10 out of 25 companies had reported any action on trying to reduce salt levels while only five were working to reduce sugar. Four out of 25 were working to reduce fat and only two, Kraft and McDonald's had taken plans to reduce portion sizes.

Their performance is by and large pathetic, said one of the report's authors, Tim Lang, a professor of food policy.

The 10 leading manufacturers included such household names as Cadbury Schweppes Plc, Coca-Cola Co, Mars, Nestle and Unilever. The leading retailers included Aldi, Carrefour, Schwartz and Tesco while the leading food service companies included Burger King, McDonalds and Yum Brands Inc. which includes Pizza Hut and KFC.

The report said the firms doing the most to improve health standards were those, such as McDonalds, who had been criticised for selling fatty and salty foods.

This suggests that the best way to get companies to take health seriously is to have critics outside giving them a hard time, Lang said.

Eventually the companies wake up. But if companies keep their heads below the parapet, no health innovation or consciousness seems to take root inside corporate culture.

A spokeswoman for the Food and Drink Federation said the industry had already made a lot of changes to tackle the problems surrounding food and health.

Industry has long recognised its responsibility in this area and will continue to work with government, educators and consumers to help tackle the problems surrounding food and health, she said.

Below is a list of the 25 companies:

Manufacturers: Cadbury, Coca-Cola, ConAgra Foods Inc, Danone , Kraft, Mars, Nestle, Pepsico Inc, Tyson Foods Inc and Unilever.

Retailers: Ahold, Aldi, Carrefour, Ito-Yokado Co. Ltd, Kroger Co., Metro, Rewe, Schwartze, Tesco and Wal-Mart Stores Inc..

Food service companies: Burger King, Compass Group Plc, McDonalds, Sodexho Alliance and Yum!

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